연세대학교 이과대학 화학과

일시: 2025년 7월 15일 오후 4시
장소: IBS Hall Auditorium
초록: One of the most fascinating effects of two-dimensional (2D) crystals is the proximity effect, which, for example, changes the band character in transition metal dichalcogenides. While destiny-functional theory (DFT), the working horse computational method in the field, correctly describes the impact of the proximity effect on the electronic structure, the prediction of interlayer distances is less straight-forward. This is an issue if the interlayer interaction can result in different isomeric structures, sometimes with strongly different electronic characteristics, such as in blue phosphorene, gray arsenene or its bilayers. As a side note, even the nomenclature of the stacking symmetry is not straight-forward. Twisted bilayers are known to form moiré structures which can further relax to stacking domains separated by superlattices, where the latter ones dominate the electronic structure near the fermi level. The emergence of 2D crystals with magnetic ordering has called for the intestigation of the interlayer magnetic interactions. Intriguingly, one can transfer magnetic moments inbetween layers by optical excitation as revealed by real-time time-dependent DFT caculations. We have recently extended our efforts to couple organic 2D crystals, which are made of organic molecules that are stitched together with strong bonds to form a regular crystal with the traditional 2D crystals. Also organic 2D crystals are subject to a strong proximity effect, and strong couplings are observed in their heterostructures with graphene.